This is a continuation of a cooperative inter-institutional study of cancer in children utilizing a multi-disciplinary approach to treatment of those types of cancer which are suited to scientific analysis in a reasonable period of time. The studies are designed to provide answers to questions concerning optimum management; and at the same time provide the individual institutions with the added strengths to provide its community with a referral center for childhood cancer. At the time of writing, there are ten active protocols dealing with leukemia and fifteen dealing with solid tumors. The principal protocol for ALL/AUL is designed to determine relative importance of front-end factors in prognosis with randomized increased therapy during maintenance for those with known poor prognostic findings. The protocol dealing with AML randomizes for BCG cells and frozen AML cells in maintenance evaluates possible immunologic therapeutic value of AML cells with BCG. A specific protocol is available for Wilms' tumor, localized and disseminated neuroblastoma, histiocytosis, retinoblastoma, brain tumor, hepatoma, osteogenic sarcoma, non-Hodgkin's lymphoma, and ovarian tumor for the group alone, as well as Rhabdomyosarcoma, Ewing's tumor on an intergroup basis. Additional protocols for the study of untreated and previously treated metastatic neuroblastoma, extraocular and bilateral retinoblastoma, histiocytosis, and pineal region germinoma are being formulated. In addition, Phase II studies are on-going utilizing a succession of agents and combinations, such as Cyclocytidine, Vindesine, VM-26, 5FU, and Cis-platinum.